Evaluating Water Exclusion Using Plastic Ground Cover In Maize At Two Population Densities

Evaluating maize (Zea mays L.) hybrids under drought conditions in rain-fed environments can be difficult using deficit irrigation practices, and installation of permanent rain-exclusion structures can be cost prohibitive. Covering the soil surface to reduce infiltration has been successful in other crops, but limited evaluation has been conducted in maize systems of the U.S. Corn Belt. The objective of this study was to determine if black plastic ground cover could exclude water from maize under varying agronomic conditions to generate dry soil conditions. A field study was conducted in South Charleston, OH, in 2013 and 2014 in maize using two hybrids with varying drought tolerance at two plant populations (74,000 and 124,000 plants ha(-1)). Black plastic ground cover was installed at canopy closure (V6) as a water exclusion practice, and a rain-fed plus irrigation treatment was also installed at V6 for comparison. Water exclusion reduced soil moisture at R2, R5, and R6 by 0.02 to 0.09 m(3) water m(-3) soil and reduced yield by 2.11 Mg ha(-1) compared to the rain-fed plus irrigation treatment. While water stress symptoms during the season were not observed, volumetric water content decreased below the permanent wilting point at R5 in the top 30 cm in 2013 and at R2, R5, and R6 in the top 20 cm in 2014. These results suggest that surface-applied black plastic can be an effective water exclusion method in maize, but should be evaluated further to optimize installation timing and its utility in suboptimal growing seasons.